Idle air valve



June 23, 1959 I DoLzA ETAL IDLE AIR VALVE 2 Sheets-Sheet 1 Filed June 6, 1957 June 23, 1959 J, DOLZA ETAL 2,891,528

I IDLE AIR VALVE Filed June 6, 1957 2 Sheets-Sheet 2 IN VENTORS United States Patent 2,891,528 Patented June 23, 1959 free IDLE AIR VALVE John Dolza, Fenton, and Stanley H. Mick, St. Clair Shores,

Mich, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application June 6, 1957, Serial No. 664,003 Claims. (Cl. 123-419) This device relates to a mechanism for controlling the idle air fiow in a fuel injection system in accordance with engine temperature.

In the past it has been customary to control idle air flow by maintaining the throttle valve in variously cracked or partially opened positions by a fast idle cam mechanism which is controlled by an engine temperature responsive mechanism. By such means under idling conditions with the engine cold the throttle was maintained in a fast idle position through engagement with a high step of the cam member with the throttle progressively engaging lower steps of the cam to move toward a more fully closed position as engine temperature increases. A fast idle cam mechanism makes it necessary to provide control linkagesbetween the fastidle cam and a normally remotely located temperature responsive mechanism. Further, with a stepped earn it is necessary, preliminary to starting, to first open the throttle after the engine has cooled to permit the throttle to move from the low step of the cam up to the high step or fast idle position forcold operation. This latter operation has eitherbeen achieved manually by the operator depressing the throttle or by suitable mechanism automatically cracking the throttle.

The present device represents a greatly simplified mechanism whereby the idle air flow is controlled by a valve mechanism intimately associated with the temperature responsive element and which arrangement permits the throttle valve to be completely closed under all idling conditions. Thus by virtue of the present mechanism it is possible to regulate idle air flow without the necessity of in any way actuating the throttle valve.

The details of the present invention as well as other objects and advantages are set forth in the description which follows.

In the drawings:

Figure 1 is a partially sectioned view of an air induction casing embodying the subject invention;

Figure 2 is a sectional view of the induction passage;

Figure 3 is a view along line 33 of Figure 1; and

Figure 4 is a view along line 44 of Figure 3.

Figure 5 illustrates a fuel injection system embodying the subject invention.

The present device is particularly adapted for use with a fuel injection system of the type shown and described in copending application Serial No. 658,091 of Dolza et al., filed May 9, 1957. Only that part of such fuel injection system will be shown and described as is necessary to an understanding of the present invention. Referring to the drawings, an air intake casing is shown at and includes an air induction passage 12 having a venturi 14 formed therein. A throttle valve 16 is disposed in the induction passage posteriorly of the venturi 14. A signal modifier valve 18 is also disposed in said induction pas- .sage anteriorly of venturi 14 and is fixed to a rotatable shaft 20.

A device adapted to meter fuel in accordance with 2 certain engine operating conditions, e.g. mass air flow through air intake casing 10, is shown generally at 11. Fuel metering device 11 is adapted to supply metered quantities of fuel through conduits 13 to individual engine cylinder nozzles 15 located in cylinder intake passages 17.

The signal modifier valve is adapted to be controlled by a temperature responsive mechanism indicated generally at 22 as described in detail in the aforenoted copending application. As best seen in Figure 4 the signal modifier valve shaft '20 projects through air casing 10 and extends within a casing 24 of the temperature responsive mechanism 22. A temperature responsive ele ment or thermostatic coil 26 is disposed in casing 24 and anchored at one end thereto. The other end 28 of the coil 26 is fixed to the signal modifier shaft 20 such that when the engine is cold the temperature responsive element is adapted to maintain the signal modifier valve 18 in a closed position to reinforce or supplement the metering vacuum control force as described in the aforenoted copending application.

Under idling conditions, the throttle valve 16 is adapted to close on the induction passage wall. To provide means for bypassing air around the throttle for suitable engine idling operation, a first longitudinally extending passage 30 is formed in the air intake casing 10 and communicates at port 31 with the induction passage 12 anteriorly of the throttle 16. The other end of passage 30 communicates with a transversely extending passage 32 disposed proximate the signal modifier shaft 20. A second longitudinally extending passage 34 is formed in air intake casing 10 and communicates at its lower end 35 with the induction passage posteriorly of the throttle valve 16. The upper end of passage 34 similarly communicates with the transversely extending passage 32.

Thus with throttle 16 closed manifold vacuum acting on the inner end 35 of passage 34 is adapted to cause air to be drawn through the transverse passage 32 and the longitudinally extending passage 30 so as to bypass air flow around said throttle. In order to vary the quantity of air bypassed around throttle 16 in accordance with engine requirements as reflected by temperature, a valve member 38 is disposed in the transverse passage 32. Valve 38 is suitably connected to the signal modifier valve mechanism in order to position the valve in response to engine temperature. More specifically valve 38 is mounted on the signal modifier shaft 20 and upon the rotation of said shaft is adapted to vary the quantity of air flowing through the transverse passage 34.

During cold idling conditions it is necessary that a maximum amount of air be bypassed around the throttle 16. Accordingly, with the engine cold, the signal modifier valve 18 will be closed as shown and the bypass flow control valve 38 is open, as shown in Figure 1, permitting maximum air flow through passages 30, 32 and 34. As the engine temperature increases and signal modifier valve 18 opens, shaft 20 will cause bypass valve 38 to progressively close the flow through the idle air bypass network. In this way a simple device is provided for controlling idle air flow which eliminates many parts previously necessary to achieve such control in the past. Further, it will be apparent that as the engine temperature cools causing the signal modifier valve to move towards a closed position the bypass control valve 38 will automatically move to an open or fast idle position without the need for actuating the throttle valve 16.

To assist in the opening of the signal modifier valve and thereby eliminating a separate vacuum piston, as is provided in the aforenoted copending application, the bypass control valve 38 may be mounted off center with respect to the signal modifier shaft 20. In this way manifold vacuum which causes the flow of idle air through the passages 30, 32 and 34 will also act on the unbalanced valve 38 to assist coil 26 in the opening of the signal modifier valve.

We claim:

1. An idle air flow control mechanism for a fuel injection system comprising an air intake casing, an air induction passage formed in said casing, a venturi formed in said air intake passage, a throttle valve rotatably disposed in said air intake passage posteriorly of said venturi, a second valve rotatably disposed in said air intake passage anteriorly of said venturi, temperature responsive means for controlling said second valve and normally biasing said valve in a closed position when cold, passage means for bypassing air around said throttle valve when closed, valve means for controlling the quantity of bypass air flow through said passage means, and means operatively connecting said bypass flow control valve with said second valve to control the quantity of bypass air flow in inverse proportion to the temperature of said temperature responsive means.

2. An idle air flow control mechanism for a fuel injection system comprising an air intake casing, an air induction passage formed in said casing, a venturi formed in said air intake passage, a throttle valve rotatably disposed in said air intake passage posteriorly of said Venturi, a second valve rotatably disposed in said air intake passage anteriorly of said venturi, temperature responsive means for controlling said second valve and normally biasing said valve in a closed position when cold, passage means for bypassing air around said throttle valve when closed, valve means disposed proximate said second valve for controlling the quantity of bypass air flow through said passage means, and means operatively connecting said bypass flow control valve with said second valve to control the quantity of by pass air flow in inverse proportion to the temperature of said temperature responsive means.

3. An idle air flow control mechanism for a fuel injection system comprising an air intake casing, an air induction passage formed in said casing, a venturi formed in said air intake passage, a throttle valve rotatably disposed in said air intake passage posteriorly of said venturi, a second valve disposed in said air intake passage anteriorly of said venturi, and second valve fixed to a shaft rotatably supported within said intake casing, temperature responsive means for controlling said second valve and normally biasing said valve in a closed position when cold, passage means for bypassing air around said throttle valve when closed, said valve shaft extending through a portion of said bypass passage means, valve means fixed to said shaft for controlling the quantity of bypass air flow through said passage means in inverse proportion to the temperature of said temperature responsive means.

4. An idle air flow control mechanism for a fuel injection system comprising an air intake casing, an air induction passage formed in said casing, a venturi formed in said air intake passage, a throttle valve rotatably disposed in said air intake passage posteriorly of said venturi, a second valve disposed in said air intake passage anteriorly of said venturi, said second valve fixed to a shaft rotatably supported within said intake casing, temperature responsive means for controlling said second valve and normally biasing said valve in a closed position when cold, a first passage formed in said casing and communicating at one end with the air intake passage anten'orly of said throttle, a second passage formed in said passage and communicating at one end with said air intake passage posteriorly of said throttle, a third passage in said casing proximate said second valve and interconnecting the other ends of said first and second passages whereby manifold vacuum will cause air to flow through said passages and bypass said throttle when closed, and a valve in said third passage, said valve being operatively connected to said second valve to control the quantity of air flow through said passages in inverse proportion to engine temperature.

5. An idle air flow control mechanism as defined in claim 4 in which said air bypass valve is fixed and unbalanced with respect to said second valve shaft permitting manifold vacuum in said passages to urge the second valve in an open direction against the force of said temperature responsive means.

No references cited. 

